Tougher times for Drug Resistant Bacteria

The Secret of how to prevent bacteria from developing drug resistance has been revealed in a new study.Drugs called bisphosphonates, widely prescribed for bone loss has been found to help in preventing an enzyme that helps in conjugation of bacteria, by help of which it derives drug resistance.

Many highly-drug resistant bacteria rely on an enzyme, called DNA relaxase, to obtain and pass on their resistance genes. Relaxase  plays a crucial role in conjugation as it is the gate keeper that starts and stops the movement of DNA between bacteria durig conjugation.

researchers at the University of North Carolina at Chapel Hill, have stopped the microbes’ ability to spread, among other advantageous mutations, resistance to antibiotics, by disabling the enzyme using molecules known as  bisphosphonates

The study by Matthew Redinbo and his associates is published in this week’s Proceedings of the National Academy of Sciences USA

The antibiotic-resistant Escherichia coli bacteria that were trying to pass their genes along, actually died when their DNA relaxase was shielded thus preveinting the spread of drug resistant bacteria andpossibility of more mutations.

The news is will bring fresh hopes at a stage when drugresistant strain of the bacteria Staphylococcus aureus infects over 1 million US hospital patients every year.

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its not so much of junk DNA- University of Oxford Scientists discoveres Cancer cure with it

 Junk DNA is not junk after all

Recently, scientists at the University of Oxford have discovered that ‘junk’ genetic material can switch off cancer tumours, preventing them from growing.

By using RNA to switch off a gene involved in controlling cell division, Oxford University scientists may have found a role for RNA in developing new cancer therapies. RNA is the mirror image of DNA, and is used to pass on instructions to the cell to build the proteins that run every body function.

The Human Genome Project found that human DNA carries approximately 34,000 genes that produce proteins. The remaining majority of the genome constituted what was considered to be junk DNA as it had no obvious function. However, this is set to change.

‘‘There has been a quiet revolution taking place in biology in past few years,’’ said Dr Alexandre Akoulitchev, a Senior Research Fellow at Oxford. ‘‘Scientists have begun to see ‘junk’ DNA as having an important function. The variety of RNA types produced from this so called ‘junk’ is staggering and the functional implications are huge.”

Akoulitchev studied the RNA that regulates a gene called DHFR. This gene produces an enzyme that controls the production of molecules called tetrahydrofolate and thymine that cells need to divide rapidly.

“Switching off the DHFR gene could help prevent ordinary cells from developing into cancerous tumour cells, by slowing down their replication. In fact, one of the first anti-cancer drugs, Methotrexate, acts by binding and inhibiting the enzyme produced by this gene. Targeting the gene itself would cut the enzyme out of the picture altogether. Understanding how we can use RNA to switch off or inhibit DHFR and other genes may have important therapeutic implications for developing new anti-cancer treatments.”

This research was funded by The Wellcome Trust and the Medical Research Council.

Original paper: Repression of the human dihydrofolate reductase gene by a non-coding interfering transcript was published in Nature on 22nd January 2006.

Microarray based Bio Detection Technologies

DNA microarray detection of antimicrobial resistance genes in diverse bacteria

Study published at http://cat.inist.fr/?aModele=afficheN&cpsidt=17459830
High throughput genotyping is essential for studying the spread of multiple antimicrobial resistance. A test oligonucleotide microarray designed to detect 94 antimicrobial resistance genes was constructed and successfully used to identify antimicrobial resistance genes in control strains. The microarray was then used to assay 51 distantly related bacteria, including Gram-negative and Gram-positive isolates, resulting in the identification of 61 different antimicrobial resistance genes in these bacteria. These results were consistent with their known gene content and resistance phenotypes. Microarray results were confirmed by polymerase chain reaction and Southern blot analysis. These results demonstrate that this approach could be used to construct a microarray to detect all sequenced antimicrobial resistance genes in nearly all bacteria.

The Insider -Code inside Codes : Scientists Discover Parallel Codes in Genes

Researchers from The Weizmann Institute of Science report the discovery of two new properties of the genetic code. Their work, which appears online in Genome Research, shows that the genetic code—used by organisms as diverse as reef coral, termites, and humans—is nearly optimal for encoding signals of any length in parallel to sequences that code for proteins. In addition, they report that the genetic code is organized so efficiently that when the cellular machinery misses a beat during protein synthesis, the process is promptly halted before energy and resources are wasted.

DNA sequences that code for proteins need to convey, in addition to the protein-coding information, several different signals at the same time. These “parallel codes” include binding sequences for regulatory and structural proteins, signals for splicing, and RNA secondary structure. Here, we show that the universal genetic code can efficiently carry arbitrary parallel codes much better than the vast majority of other possible genetic codes. This property is related to the identity of the stop codons. We find that the ability to support parallel codes is strongly tied to another useful property of the genetic code—minimization of the effects of frame-shift translation errors. Whereas many of the known regulatory codes reside in nontranslated regions of the genome, the present findings suggest that protein-coding regions can readily carry abundant additional information.

“Our findings open the possibility that genes can carry additional, currently unknown codes,” explains Dr. Uri Alon, principal investigator on the project. “These findings point at possible selection forces that may have shaped the universal genetic code.”

The genetic code consists of 61 codons—tri-nucleotide sequences of DNA—that encode 20 amino acids, the building blocks of proteins. In addition, three codons signal the cellular machinery to stop protein synthesis after a full-length protein is built.

While the best-known function of genes is to code for proteins, the DNA sequences of genes also harbor signals for folding, organization, regulation, and splicing. These DNA sequences are typically a bit longer: from four to 150 or more nucleotides in length.

 

Store Digital data with live bacteria

A research team said this week it had developed a technology for storing digital data in the DNA of bacteria, which unlike most living organisms can survive for millennia in the right conditions.

Japanese researchers have successfully stored messages in the DNA of bacteria. The hardiness of the hay bacillus bacteria ensures the digital data encoded into them can last for millenia.

Generally found in soil or decaying matter, hay bacillus are exceptionally resistant to extreme weather conditions. Two megabits (data equivalent to 1.6 million Roman letters) can be stored in each bacterium of hay bacillus in the form of implants. These tiny implants can be extracted in a lab and read like ordinary text at a later date.

Each hay bacillus bacterium can store two megabits — the equivalent of 1.6 million Roman letters. The scientists can take out the microscopic implants in a laboratory and read them so they appear as ordinary text.

The team at Keio University’s Institute for Advanced Biosciences said the technology needs to be perfected but that it was optimistic about its future uses.

“If I wanted to store my personal diary in these live bacteria and take it with me to my grave, then my story can live for thousands and thousands of years,” head researcher Yoshiaki Ohashi said with a laugh.

In practical terms, the technology could eventually benefit companies such as pharmaceutical makers which want to “stamp” their brand.

“In doing so, the company can detect piracy and protect its patent. They can also store information at one specific area of the gene and retrieve it from there,” Ohashi said.

The researchers insert the data at four different places so even if one is disrupted, there would be backup.

But the team said they still needed to work before the technology could go on the market. In particular, the scientists need to ensure that the DNA will not be altered as live bacteria naturally evolve.

Hay bacillus bacteria are generally found in soil or decaying matter and are especially resistant to extreme weather.

One of the practical applications of this technology lies in the area of pharmaceuticals. Fraudulent drugs are a major problem but if pharmaceutical companies could “stamp” their signature into the drugs, it would prevent piracy and at the same time protect their patents. To prevent corruption of the message encoding, the data would be inserted into 4 different places as multiple backups.
The bacteria’s hardiness and ability to preserve data for future generations would also be extremely useful in storing vast amounts of data which would not be suspectible to the types of damage that wipe out computer hard drives. Information stored on DNA lasts for more than one hundred million years.

The researchers project being able to develop a type of living memory for a new breed of organic computers which would use strands of DNA to perform calculations and would have the ability to heal themselves if damaged.

Though the promise of this technology is very high, the scientists caution more work is needed before it can be marketed. One of the hurdles to overcome is ensuring very slow mutation rates in the DNA as the bacteria evolve, otherwise the messages encoded will be rendered unreadable.

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